Distribution of some volatile nitrosamines in cooked bacon

Bacon was fried in the normal UK domestic manner, and the rashers, the cooked-out fat and the vapour were analysed for N-nitrosopyrrolidine and N-nitrosodimethylamine. Quantitative results were based on high resolution mass spectral measurements, and it was found that for both of the nitrosamines by far the greatest proportion occurred in the vapour.     

Volatile, non-volatile and total N-nitroso compounds in bacon.

Twenty-five smoked and unsmoked fried bacon samples have been analysed by a group selective procedure to measure the concentration of apparent total N-nitroso compounds (ATNC). The levels of a range of individual N-nitroso compounds, including simple volatile N-nitrosamines, N-nitrosothiazolidines, N-nitrosamino acids and N-nitrosothiazolidine carboxylic acids have also been examined. Concentrations of ATNC varied from 430 to 6800 micrograms(N-NO)/kg with a mean of 2700 micrograms(N-NO)/kg. Protein-bound N-nitrosoproline was the most abundant compound detected in unsmoked bacon, mean 260 micrograms/kg, and on average accounted for 4% of the ATNC concentration. For smoked bacon, bound N-nitrosoproline was detected in levels of up to 890 micrograms/kg and contributed 5% to the ATNC total. The most abundant compound present in smoked bacon was N-nitrosothiazolidine-4-carboxylic acid, mean 660 micrograms/kg, and this accounted for 6% of the ATNC. N-Nitrosothiazolidine, mean 340 micrograms/kg, and 2-(hydroxymethyl)-3-nitrosothiazolidine-4-carboxylic acid, mean 180 micrograms/kg, were the next most prominent compounds detected in smoked bacon. The combined sum of all the individual N-nitroso compounds measured accounted for, on average, 16% of the total ATNC. The identities of the N-nitroso compounds comprising the majority of the ATNC in bacon remain unknown.     

The effect of antioxidants on the production, of volatile nitrosamines during the frying of bacon

Summary In model system studies simulating the frying of bacon a considerable variation in the production of N-nitrosopyrrolidine (NOPyr) has been observed, as occurs in sliced bacon fried conventionally. The inclusion of ascorbate or erythorbate (isoascorbate) has led consistently to a fall in or an elimination of NOPyr production up to an addition of 300 ppm (1,5 mM). Above this concentration of ascorbate, the elimination of NOPyr formation persisted in some instances but in others an increased production of the nitrosamine occurred. Using-tocopherol, a fall of NOPyr production during the simulated frying of bacon was obtained with increase of concentration of the antioxidant, there being a consistent elimination of the volatile nitrosamine following an addition of 500 ppm (1.16 mM). Whilst ascorbyl palmitate had a similar action in reducing or eliminating NOPyr production, no synergistic effect between it and a-tocopherol was noted in an experiment combining the two antioxidants. When bacon was fried in fat containing 400 or 800 ppm-tocopherol, the total production of NOPyr and DMN in the fried bacon, cooked out fat and condensate was markedly reduced but not completely eliminated as in the model system studies. Similarly, the curing of bacon with a brine containing a mixture of-tocopherol, ascorbyl palmitate and citric acid has led to considerable reductions in NOPyr and DMN output on frying when the combined concentrations of the two anti-oxidants were calculated to be 800 ppm.

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Der Einfluß von Antioxydantien auf die Entwicklung flüchtiger Nitrosamine während des Bratens von Speck

Zusammenfassung Bei Untersuchungen in Modell-Systemen, in denen das Braten von Speck simuliert wurde, stellte man eine nennenswerte Variation in der Entstehung von N-Nitrosopyrrolidin (NOPyr) fest, wie sie auch bei konventionell gebratenem Scheibenspeck auftritt. Der Zusatz von Ascorbat oder Isoascorbat hat bei einem Zusatz bis zu 300 ppm (1,5 mmol) regelmäßig zur Abnahme der NOPyr-Produktion geführt. Bei größerer Ascorbatkonzentration nahm die NOPyr-Bildung in einigen Fällen ab, in anderen setzte dagegen eine erhöhte Nitrosaminbildung ein. Bei Anwendung von-Tokopherol wurde eine Abnahme in der NOPyr-Bildung während des simulierten Bratens von Speck bei zunehmender Antioxydantien-Konzentration erreicht, wobei ein gleichbleibendes Verschwinden des flüchtigen Nitrosamins eine Folge des Zusatzes von 500 ppm (1,16 mmol) war. Während Ascorbylpalmitat eine ähnliche Wirkung in der Reduzierung der NOPyr-Bildung hatte, konnte bei einem Experiment, bei dem die beiden Antioxydantien zugegen waren, keine synergistische Wirkung festgestellt werden. Wenn Speck in 400 oder 800 ppm-Tokopherol enthaltendem Fett gebraten wude, war die Gesamtbildung von NOPyr und DMN in dem gebratenen Speck, dem ausgekochten Fett und im Kondensat wesentlich reduziert, aber nicht wie bei den Modell-System-Versuchen vollständig eliminiert. Ähnlich führte auch das Pökeln von Speck in Lake, die eine Mischung von-Tokopherol, Ascorbylpalmitat und Citronensäure enthielt, zu wesentlicher Reduzierung in NOPyr- und DMN-Produktion beim Braten, wenn die Konzentration der beiden Antioxydatien zusammen auf 800 ppm berechnet wurden.

     

The effect of antioxidants on the production of volatile nitrosamines during the frying of bacon.

In model system studies simulating the frying of bacon a considerable variation in the production of N-nitrosopyrrolidine (NOPyr) has been observed, as occurs in sliced bacon fried conventionally. The inclusion of ascorbate or erythorbate (isoacorbate) has led consistently to a fall in or an elimination of NOPyr production up to an addition of 300 ppm (1,5 mM). Above this concentration of ascorbate, the elimination of NOPyr formation persisted in some instances but in others an increased production of the nitrosamine occurred. Using alpha-tocopherol, a fall of NOPyr production during the simulated frying of bacon was obtained with increase of concentration of the antioxidant, there being a consistent elimination of the volatile nitrosamine following an additionof 500 ppm (1.16 mM). Whilst ascorbyl palmitate had a similar action in reducing or eliminating NOPyr production, no synergistic effect between it and alpha-tocopherol was noted in an experiment combining the two antioxidants. When bacon was fried in fat containing 400 or 800 ppm alpha-tocopherol, the total production of NOPyr and DMN in the fried bacon, cooked out fat and condensate was markedly reduced but not completely eliminated as in the model system studies. Similarly, the curing of bacon with a brine containing a mixture of alpha-tocopherol, ascorbyl palmitate and citric acid has led to considerable reductions in NOPyr and DMN output on frying when the combined concentrations of the two anti-oxidants were calculated to be 800 ppm.     

微波烤虾保藏技术研究

试验研究了不同杀菌方式及贮藏时间对微波烤虾品质的影响。结果表明,2kGy辐照和常压杀菌只能有限地降低腐败微生物数量,长期保存还必须结合冷藏。6、8kGy辐照杀菌能有效降低微波烤虾腐败微生物含量,达到商业无菌,但在常温保存6个月后,甘氨酸明显降低,造成虾肉鲜味不足。     

Volatile nitrosamines in foods on the Swedish market and estimation of their daily intake

Foods on the Swedish market in 1980-1986 were analysed for volatile N-nitrosamines using gas chromatography-thermal energy analysis. Detectable levels were found in 474 of the 764 samples analysed. The average daily intake of volatile N-nitrosamines was estimated to be 0.29 microgram per person. Over 93% of the intake comes from meat and malt products.     

N-Nitrosopyrrolidine formation in bacon

Evidence is presented that the likely major amine precursors to N-nitrosopyrrolidine in cooked bacon are free proline in the adipose tissue and to a lesser extent, collagenous connective tissues. A model system in which animal lipid is replaced with hydrogenated vegetable oil is described and used in investigating the potential role of prolyl derivatives as precursors to N-nitrosopyrrolidine.     

Hot curing Wiltshire bacon

A process combining multi-needle injection and dry salting of whole baconsides before they have been completely chilled can produce acceptable Wiltshire bacon in only 5 days from slaughter. Eating quality and storage stability of sliced and vacuum packed, hot cured bacon were similar to those of dry salted bacon made from conventionally chilled sides. The yields of hot cured and cold cured raw bacon were similar, but cooking yields of hams were over 3.0% higher with hot curing.
A continuous hot curing process from slaughter, through carcass preparation, multi-needle brine injection, dry salting to chilling could simplify Wiltshire bacon processing. The concept could be particularly useful to a processor lacking the specialized facilities for traditional immersion curing.     

腊肉风味的研究

介绍了国内外关于肉类风味的研究现状,其中包括肉类风味前体物质、产生肉类风味的反应和产生肉香的挥发性风味化合物,重点论述了产生腊肉风味的化学物质以及影响腊肉风味的因素。     

离线纸箱编码器的成功之路

Pork Farms公司目前挑选了Allen公司的4ACC离线纸箱编码器来替换位于沙夫茨伯里的工厂里的一台旧机器。Allen编码系统公司因其有竞争力的价格和丰富的经验使其成为了最终选择。Pork Farms公司是苏格兰的一家生产制造鸡蛋、酥烤食品和熟鸡尾酒香肠的厂家,他们选择4ACC离线纸箱编码系统来应对产品包装的新需求,比如装有乐购的南部炸鸡和迷你鸡蛋的零食罐。Pork Farms公司的总工程师SimonGreenwood称:Allen公司的机器最大的特点就是便于操作,并且能够快速     

Reduction of nitrosamines in cosmetic products

From initial rate studies of morpholine nitrosation in aqueous media by nitrite ion in the presence of formaldehyde at pH 5–7 and 25°C, four potential pathways are revealed for the concurrent formation of nitrosamine contaminants in cosmetic and toiletry products. Three of the pathways involve conventional electrophilic nitrosation by XNO reagents of both neutral amine and N -hydroxymethylamine compounds obtained by prior reaction with formaldehyde. The fourth pathway involves a nucleophilic reaction by nitrite ion with the iminium ion derived from N -hydroxymethylamine. For morpholine, reaction via XNO reagents is substantial at pH 5 only, whereas the iminium ion pathway is pre-eminent at pH 7. The concurrent formation of nitrosamines by mechanistically different pathways implies that combinations of nitrosation inhibitors are necessary to minimize contamination of cosmetic and toiletry products. For these different pathways, novel inhibitory compounds are described which fulfil the usual acceptance criteria for cosmetic and toiletry materials. The efficacy of these compounds is assessed against N -nitrosomorpholine formation in the presence of formaldehyde. These include erythorbate, ascorbate, pentanedione and pyranone compounds for the XNO pathways (pH 6) and neutral organic and inorganic salts for the iminium ion pathways (pH 7). Preliminary results for both a bath gel and a cream-base formulation deliberately adulterated with morpholine, diethanolamine, nitrite and a preservative which releases low levels of formaldehyde on decomposition show better than 90% inhibition of nitrosamines by selected pairs of inhibitor compounds on storage at 40°C over several months. This novel technology is the subject of a worldwide patent application.     

牛肉培根加工工艺

介绍了牛肉培根的加工方法.以优质牛腰窝为原料,通过试验确定了最佳腌制配方,即食盐添加量2.5%,白糖添加量0.8%,水添加量22%,腌制时间24h;以及最佳烟熏工艺参数,即烟熏温度65℃,时间40min时,牛肉培根品质最好.     

腊肉产业存在的问题及应对措施

腊肉作为中国饮食文化中的瑰宝, 在肉制品的组成中占有重要的地位。近年来学者们对腊肉的研究大多集中于如何提高其发色效果、抑菌能力、风味增强和氧化稳定性以及各种腌制、熏制等新式工艺设备的研发, 目的在于更好地推进腊肉的工业化和现代化, 提高品质, 促进腊肉经济的发展。发现并解决腊肉存在的问题是提高其品质的必然途径。深入探究腊肉存在的主要问题并研究其应对措施, 对其高品质的形成具有重要意义。本文分析了腊肉存在的亚硝酸盐残留量高、脂肪氧化严重、生产工艺相对落后、食用麻烦以及含有苯并芘等问题, 并综述了其应对措施, 以期为腊肉的加工、贮藏及新品开发提供借鉴。     

发酵培根加工技术的研究

系统地探讨了发酵培根的加工工艺，通过对发酵温度、发酵时间、接种量及NaCl等几个关键因素进行正交实验，表明培根原料经整理、切块后，采用干腌法将肉腌制48h，并添加1．0％的乳酸菌于30℃温度下进行快速发酵，随后进行烘烤，色香味俱佳。具有明显保健作用的低温发酵培根。     

Boar bacon: A consumer survey

Boar bacon and castrate bacon were submitted to a consumer test in 525 households. Visual acceptability and cooking judgements were provided by 525 respondents and eating judgements by 1066. Each characteristic was rated on a seven-point scale. On most characteristics fewer than 1% of either cooks or eaters marked the boar very unfavourably. Only on strength of aroma during cooking did a sizeable proportion of respondents (13%) give boars an extreme score, and in most cases this was associated with a favourable score for appetisingness of aroma. Only three of these individuals, or 0.6% of the sample, considered it much or very much less appetising than usual and none of them considered it to have a much or very much less pleasant flavour.     

Effect of water on nitrosamine formation in fried bacon

Bacon was soaked in water before frying and the effect on the formation of N-nitrosodimethylamine and N-nitrosopyrrolidine was studied. Soaking for 5 minutes reduced N-nitrosopyrrolidine levels by as much as 52%, but had little effect on N-nitrosodimethylamine levels. Longer soaking periods, up to 17 hours, gave the same results.     

Hydrocarbons detected in irradiated pork,bacon and ham

Hydrocarbons produced by γ-radiation of pork, bacon and ham were analyzed to determine how irradiation affects the production of the hydrocarbons and whether the hydrocarbons can be used for identifying post-irradiation of pork, bacon and ham. Hydrocarbons were determined by a sequential procedure of lipid extraction by hexane, Florisil column chromatography and gas chromatography. Hydrocarbons C17:1, C16:2, C17:2 and C16:3 were detected in pork, bacon and ham irradiated at 0.5 kGy or higher, but not in non-irradiated ones except C17:1. The detection levels in all the irradiated samples were in the order of C16:2, C17:1, C17:2 and C16:3 from the highest to the lowest.